Tire cord adhesive

ABSTRACT

THIS INVENTION RELATES TO THE METHOD OF BONDING A VULCANIZED RUBBER COMPOSITION TO A TEXTILE MATERIAL AND THE LAMINATE PRODUCED. PARTICULAR ADHESIVE ENHANCING INGREDIENTS ARE ADDED TO THE RUBBER BEFORE VULCANIZATION TO PRODUCE A BETTER BOND BETWEEN THE VULCANIZED RUBBER AND THE TEXTILE MATERIAL.

United States Patent Ofice 3,598,690 Patented Aug. 10, 1971 3,598,690 TIRE CORD ADHESIVE Arthur C. Danielson, Royal Oak, Mich., assignor to Uniroyal, Inc., New York, N.Y. No Drawing. Filed Nov. 21, 1967, Ser. No. 684,645 Int. Cl. B29h 17/28 U.S. Cl. 161-144 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the method of bonding a vulcanized rubber composition to a textile material and the laminate produced. Particular adhesive enhancing ingredients are added to the rubber before vulcanization to produce a better bond between the vulcanized rubber and the textile material.

In certain rubber articles designed to withstand considerable stresses in use, the rubber is reinforced with plies of comparatively inextensible textile materials. Thus, rubber hose, belts and tires are commonly reinforced with filamentary textiles in the form of yarns, cords or fabric. In such articles, it is important that the plies of textile reinforcing material be firmly adhered to the rubber intermediate the textile plies and remain effectively adhered even after the article has been subjected to repeated varying strains in use, because any separation and relative movement of the rubber and textile parts leads to abrasion between these parts and consequent failure. In order to improve the adhesion of the textile material to the rubber intermediate the textile plies, it is common practice to first apply a deposit of rubber on the textile material, such as a tire cord fabric, by passing the textile material through a bath of an aqueous dispersion of rubber, such as a rubber latex composition, as in a so-called solutioning treatment, and drying. The rubber latex solutioning composition preferably contains a resin, e.g., a fusible partially reacted resorcinol-formaldehyde resin, such as a condensate of resorcinol and formaldehyde in the ratio of 1 mole of resorcinol to about 0.5 to 0.8 mole of formaldehyde, and formaldehyde or a formaldehydeyielding agent which on subsequent heating as during vulcanization of the rubber intermediate the textile plies cures the fusible resin to an infusible state.

According to one aspect of the present invention, there is obtained a further improvement in adhesion of the textile material to the rubber intermediate the textile plies in addition to that obtained by the latex solutioning treatment of the textile material. Also, improved adhesion can be obtained between rubber and untreated textile material.

In carrying out the present invention, adhesion of the textile material, which may be bare (so-called grey) or which may be latex solutioned, to the rubber layers intermediate the textile plies is greatly improved by incorporating in the solid rubber intermediate the textile plies a nitroamine, as hereinafter defined, and a resorcinoltype compound, viz., resorcinol or other meta disubstituted benzenes in which each of the substituents is an OH, NH or OCOCH radical (e.g. m-aminophenol, mphenylenediamine, resorcinol monoacetate, resorcinol diacetate), or 1,5 naphthalenediol, or a fusible partially reacted resorcinol-formaldehyde resin (condensate of resorcinol and formaldehyde in the ratio of one mole of resorcinol to about 0.5 to 0.8 mole of formaldehyde), or a condensation product of resorcinol and acetone (condensate of reosrcinol and acetone in the ratio of one mole of resorcinol to about 0.5 to 2 moles of acetone), or a condensation product of resorcinol and acetaldehyde (condensate of resorcinol and acetaldehyde in the ratio of one mole of resorcinol to about 0.5 to 1 mole of acetaldehyde). Such fusible partially reacted resorcinol-formaldehyde resins and those used in the above mentioned latex solutioning compositions may be prepared in known manner by heating a concentrated aqueous solution of the resorcinol and formaldehyde, with or without a catalyst such as oxalic acid. The ball and ring softening point (ASTM designation E2 8-58T) of such fusible partially reacted resins 'will generally be from about 60 C. to 120 C. Such resorcinol-acetone condensates, which are white powders, may be prepared in known manner by reacting the acetone and resorcinol in dilute hydrochloric acid solution at temperatures from 35 C. to 50 C. for several hours. Such resorcinol-acetaldehyde condensates, which are tacky reddish oils, may be prepared in known manner by reacting the acetaldehyde and resorcinol in dilute oxalic acid solution at C., for several hours.

The nitroamines useful in the invention all have a nitro carbon bonded to an amino methyl carbon and may be represented by the following formulas:

oH,0 R3 R4 (2) R R R l 5 CHz CHr-N R3 N02 R0 and 3-cH,-NX R4 N O;

wherein R and R are hydrogen, aliphatic or aromatic groups having 1 to 18, preferably 1 to '8, carbon atoms, R and R are aliphatic or aromatic groups having 1 to 18, preferably 1 to 8, carbon atoms and R and R are hydrogen, or an aliphatic group having 1 to 18, preferably 1 to '6, carbon atoms. Additionally, R and R and R and R may be joined together to form a saturated heterocyclic ring with the nitrogen atoms, and R and R may be joined together to form a saturated homocyclic or heterocyclic ring. Such groups have from 3 to 8 members and include the pyrrolidine, oxazolidine, tetrahydro-1,3,4- oxadiazole, dihydro-1,2,3-dioxazole, piperidine, piperazine, morpholine and cycloalkyl rings. X is an alkylene group containing 1 to 8 carbon atoms. 'Examples of the aliphatic groups are alkyl, haloalkyl, hydroxyalkyl, dialkylaminoalkyl, alkoxyalkyl, aralkyl, alkenyl, aryl. Examples of the aromatic groups are aryl, alkaryl, and carboxyaryl.

Of the aforesaid nitroamines certain of these are new compositions of matter, namely, those wherein R or R and R are tertiary alkyl groups having from 4 to 18 carbon atoms. These groups are, for example, tertiarybutyl or tertiary octyl groups. Such compounds are particularly useful for incorporation into rubber because of their ease of dispersion in the rubber stock.

The preparation of these type compounds is well known in the art. See specifically, Murrary Senkus, JACS, 68, 10 (1946); Hal G. Johnson, JACS, 68, 12 (1946); and Hal G. Johnson, JACS, 68, 14 (1946).

The rubber intermediate the textile plies may be applied in the usual manner by calendering a coating of a solid vulcanizable rubber composition containing the nitroamines and the resorcinol-type compound on the textile material, generally on both sides, e.g., as in the conventional coating of tire cord fabric with tire carcass stock. Both ingredients may be mixed with the conventional compounding ingredients in the solid rubber in a 3 Banbury mixer and the rubber composition then calendered on the textile material. After building the rubbercoated textile material into the finished article, e.g., a tire, the assembly is heated to vulcanize the rubber components thereof. The ratio of the two compounds is not critical and generally will be from 0.4 to 4 parts of nitroamine per part of the resorcinol-type compound. The amount of the two compounds mixed with the rubber is not critical. Generally 0.5 to 8 parts, and preferably 1 to 4 parts, of the nitroamine and the resorcinol-type compound (total) per 100 parts of the rubber will be mixed in the rubber compound to be calendered on the textile material. Where the textile material is passed through a rubber latex solutioning bath and dried, the

ber intermediate the plies will also contain conventional compounding and vulcanizing ingredients such as carbon black, rubber processing or softening oils which may be added as such or may be present from oil-extended rubbers, antioxidants, sulfur, zinc oxide and accelerators. The textile material may be any of the conventional textiles used for reinforcing rubber, such as native cellulose (e.g. cottons), regenerated cellulose (e.g. rayons), synthetic linear polyamides (e.g. nylons), and polyesters (e.g. poly(ethylene terephthalate)), and may comprise cords or woven fabrics.

The following examples illustrate the invention. All parts and percentages referred to herein are by weight.

EXAMPLE 1 deposit on the thus treated textile material will be in the range of 1 to 15 percent, preferably 2 to 10 percent, of A rubber Compound Was P p y mlXlhg 100 Parts latex solids based on the weight of the textile material. nawtal rubber. 33 parts o carbon black. 10 pa of The solid rubber used in the present invention for Z111c OXlde, 2 Parts of t e 5 P of P t making the rubber and fabric laminates for use in tire Softener, Parts Of ahtleXldaIlt (eehdensatlell manufacture and for other purposes may be natural Product of acetone ahdelphehylamlhe), P of (Hevea) rubber o conjugated diolefine polymer Syncelerator (N-tertrary-butyl-Z-benzothiazole-sulfenthetic rubber or mixtures of any of them including their 9 P t Of S11 1f11freclaims. The aqueous dispersion of rubber, when used Addltlehelly, Venous llltheatnlhes e TeSOTCIIIOI-tSfPe for solutioning the textile material before plying with Compounds Were added as lndleated 111 the tables Whleh the solid rubber composition, may be natural rubber latex, telleW- or a latex of conjugated diolefine polymer synthetic rub- Control rubber Compounds Were P p e elmllarly t0 ber, or mixture thereof, or an aqueous dispersion of rethe above pe e P the e yp claim from such rubbers, or mixtures of any of such Pound and t mtreemlhe Were Omlttedlatices and reclaim dispersions. Such conjugated diolefine The edhesloh of h rubber eempeuhds and the C011- polymer synthetic rubbers are polymers of butadienestrots to here tlre Cords made of rayon, nylon and 1,3, e.g. butadiene-l,3, isoprene, 2,3-dimethyl-butadiene- Polyester fibers f measured at y the l,3, and copolymers of mixtures thereof, and copolymers hesleh test diseflbed 111 World, f P of mixtures of one or more such butadienes-1,3, with 213 (1 fi y 0f e e for Evaluetlhg the one or more other polymerizable compounds which are Adheslve, pe 0f p q 111 Natural and capable of forming rubbery copolymers with butadienes- Rubbers and 111 ASTM de$1ghet1H D2138-62T- In thlS 1 3, for example, up to 0% by Weight of such mixture of test, the cord under test coated with the rubber comone or more monoethylenic compounds which contain a Pound under test is embedded 111 tWO ep Standard CH =C group where at least one of th di t d rubber blocks and the assembly vulcanize. The pounds valences is attached to an electronegative group, that is, necessary to R1111 the adhered F free of e Of the a group which substantially increases the electrical dis- 40 rubber blocks 15 the attheslen Value The hlgher the symmetry or polar character of the molecule. Examples figure, the hettet the adheeloll 0f the rubber eoetlng to of compounds which contain a CH =C group and are the eotd- Test p e the h Compounds and the copolymerizable with butadienes-l,3 are aryl olefines, controls were vulcammd 30 mmutes a The y such as styrene, vinyl toluene, alpha methyl styrene, chlo- 001111018 average for y nylon, and rostyrene, dichlorostyrene, vinyl naphthalene; the alpha 2.9 lbs. for the polyester. methylene carboxylic acids and their esters, nitriles and Table I Illustrates the results Obtamed Wlth the nitroamides, such as acrylic acid, methyl acrylate, methyl amlhes g the formula methacrylate, acrylonitrile, methacrylonitrile, methacryl- R R u e c l 3 amide; vinyl pyndmes, such as 2-v1nyl pyridine, 2-methyl- 5-vinyl pyridine; methyl vinyl ketone. Examples of such conjugated diolefine polymer synthetic rubbers are poly- R; 1 R4 butadiene, polyisoprene, butadiene-styrene copolymers N02 (SBR) and butadiene-acrylonitrile copolymers. The rubwhere R1, 2, 3 and 4 are as Previously defined:

TABLE I Grey cord 250 F. H

adhesion (lbs.)

Reaetants Parts Rayon Nylon Dacron N-(Z-nitrolsobutyl)methylamine- 1. Resorciuo1 1. 25 9. 0 7. 8 3. 5 m-Aminophenol 1. 25 11 5 12.0 3.6 m-Phenylenediamine 1. 25 8 0 5 5 3.3

N-(Z-uitroisobutyl)ethylamine 1.82 Resorclnol... 1.25 8.5 7 4 3.8 m-Aminophenol- 1.25 11.4 12 9 4.1 Resorcinol mnn v 1.72 8.3 8 8 4. 5

N-(2-nitrolsobutyl) isopropylamine. 2. O0 Resorcinol monobenzoate 2.43 4.6 5.0 3.5 Resorcinol. 1 25 8.7 8.9 4.1 Resorciuol monacetate 1. 73 8. 9 7. 7 4. 9 Resorcinol-acetone condensation product 2.00 7.3 5.1 6.3 m-Phenylenediaeetate 2.20 5.6 5.6 3.8 m-Amiuophenol l. 25 12. 0 14. 4 5. 0 m-Phenylenediamine 1.25 10.4 8.7 3. 9 A partially reacted resoreinol-formaldehyde resin- 2. 00 7. 3 6.0 3. 9 1,5 naphthalcnediol" 2. 00 s. 5 7.8 5. 2

N-(2-nitr0isobutyl)n-propyla'm 2. 00 Resorcinol. 1. 25 8. 5 7. 5 4. 9 Resorelnol monoacetate 1. 72 10.0 8. 8 5. 8 m-Aminophenol 1. 25 12.0 11.9 5.0

TABLE I-Cntinued Grey cord 250 F. 11"

adhesion Obs.)

Reaotants Parts Rayon Nylon Dacron N-(2-m'troisobutyl)oxazolidine (not dist.) 1. 22 Resorcinol m-Aminophenol. Resorcinol monoacetate N-(z-nitroisobutyl)4,4-dimethyloxazolidine (not dist.) 1. 40 Resoroinol m-Aminophenol- 1,5-naphthalenediol N-(2-nitroisobutyl)dlallylamine Resorcin m-Aminophenol- 1,5-naphthalenediol N-(2-nitroisobutyl) N-methyl-n-butylamine 2. 65

Resorcinol 1. 25 9. 4 10. 9 4. 9

m-Aminophenol- 1. 25 12 3 12. 8 4. 3

Resorcinol monoacetate 1. 72 9 8 13. 5. 1

N-(Z-nitroisobutyl)2,6-dimethylmorph0line 3.02

Resoreinol 1. 8. 1 6. 7 4. 8 1. 25 13.6 14 3 3 1 m-Aminophenol Table 11 illustrates the results obtained with the nitrodiamines having the formula,

wherein R R R R and R are as previously defined:

TABLE II Grey cord 250 F. H adhesion (1bs.)

Reaetants Par s Rayon Nylon Dacron 2-nitro-2-methyl1,2-di-is0pl0py1amin0P OPEII 3.10 Resoreinol 1. 25 8. 6 8. 9 6. 2 Resorcinol mono-acetate l. 73 6. 6 5. 8 5. 3 Resorclnol-acetoue condensation prod 2. 00 5. 0 4. 7 4. 7 1,5-naphthalenediol 8. 6 8. 8 8. 0 m-AmlnophenoLu 1. 25 8.8 11. 3 6. 4 4-amino salicylic acld 1. 74 4. 7 5.3 3, 9 Resorcinol phosphate (monohydrat 1. 4. 8 6. 2 5. 9 O,N diacetyl S-aminophenol 2. 20 4. 0 4. 1 4, 1

N,Ndi(t-butyl) 2-rnethyl-2-nitr0 1,3-propanediamine Resorcinol m-Aminophen 1,5-naphtha1enediol Resorcinol phosphate (monohydrate) N,Ndi(t-octyl)2-methyl Z-nitro 1,3-propanediamine (crude) Resorcinol m-Aminophenol Resorcinol monoacetate N,Ndipheny1, 2methyl, 2-nitro 1,3-propanediamine 1.

Resorcinol Resorcmol monoaeetate Resorelnol-acetone condensation product N,N,N,Ntetraethyl 2-methy1 2-nitro 1,3-propenediamine Resorcinol m-Aminophenol N,N'di(t-butyl)2-ethyl 2-n1tr0 1,3-propanediamine (crude) 3.

Resoreinol m-Arninophenol. Resorcinol monoacetate N ,N'di(t-buty1) z-methylol 2-nitro 1,3-propanediamine 4. 00 Resorcinol 15 6, m-Aminophenol 6 N,Nbis(hydroxy-t-butyl)Z-nitro 2-methyl 1,3-propanediamine Resoreinol m-Aminophenol Table HI shows the results obtained using the bisnitroamines having the formula: (0

Rs R1 c-oH -1 I- I R4 N0. 3

wherein R R and R are as previously defined:

TABLE III Grey cord 250 F. "H" adhesion (lbs.)

Reaetants Parts Rayon Nylon Dacron N,Nbis(Z-nitroisobutyl)ethylenediamlne (crude) 18. 5 .L Resorclnol 11. 10. 3 5. 7 rn-Aminophenol. 13. 2 10. 8 6. 2 1,5-naphthalenediol 2.00 15.4 11.3 6.9

N,Nbis(2-nitroisobutyl)1,3-propanediamine (crude) 1 95 Resorcinol 15. 0 11. 6. 0 In-Amjnophenol 14. 1 12.6 6. 0 1,5-naphthalenediol 2.00 15.5 10.9 7.2

N,Nbis(2-nitroisobutyl)1,4-butauediamine (crude) t. 2. 05 Resorcinol 1. 11.9 8. 7 4. 5 m-Aminophenol 1. 25 9. 7 6.6 4. 9 1,5-naphthalenedio 00 12. 8 10. 9 5. l

N,Nbis(2-nltroisobutyl)1,6-hexanediamiue (crude) 2 25 Resorcin m-AminophenoL.

1 Ernaphthalene diol N,N'-di(2-nitrois0butyl)1,8-menthanediamine Resoreinol m-Aminophenol. A partially reacted Bis-(N-(2-nitroisobutyl)methylamino)methane Bis (N(Z-nitroisobutyl)ethylamino)methane 1. 41 .ffi

Resorcinol monoacetate 1. 72

Bis(N (2-nitroisobutyl)isobutylamino)n1ethane (crude) 1. 68 Resorcinol 1.25 m-Aminophenol 1. 25

The aforesaid data clearly establish the usefulness of the nitroamines of the invention for improving adhesivity of textile cords to rubber. Particularly noteworthy is the consistent and significant improvement of the adhesion to the untreated polyester cord.

In view of the many changes and modifications that may be made without departing from the principles underlying the invention, reference should be made to the appended claims for an understanding of the scope of the protection afforded the invention.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. In the method of laminating textile material and rubber by contacting a solid vulcanizable rubber composition with a textile material and heating the assembly to vulcanize the rubber, the step which comprises incorporating in the rubber before vulcanization a (1) a nitroamine having the nitro-carbon bonded to an aminomethyl carbon, and (2) resorcinol, m-aminophenol, m-phenylene di amine, resorcinol monoacetate, resorcinol diacetate, 1,5- naphthalenediol, partially reacted resorcinol-formaldehyde resins, condensation products of resorcinol and acetone, or condensation products of resorcinol and acetaldehyde.

2. The method of claim 1 wherein the textile material contains the dried deposit of a rubber latex treating bath.

3. The method of claim 1 wherein the nitroamine has wherein R and R are hydrogen, an aliphatic or an aromatic group containing from 1 to 18 carbon atoms, R and R are an aliphatic or an aromatic group containing 1 to 18 carbon atoms, or R and R or R and R may form, withthe nitrogen atom, a heterocyclic ring; R and R are hydrogen, an aliphatic group containing from 1 to 18 carbon atoms, or R and R may form, with the nitrocarbon, a saturated homocyclic or heterocyclic ring; and X is an alkylene group having from 1 to 8 carbon atoms.

4. The method of claim 1 wherein said nitroamine is N,N'-di (t-butyl) Z-methyl-Z-nitro-1,3-propanediamine.

5. The method of claim 1 wherein said nitroamine is N,N di(t-butyl)2-methanol-2-nitro-1,3-propanediamine.

the formula; 7 6. The method of claim 1 wherein said nitroamine is R! R3 N,N-bis(2-nitroisobutyl)ethylenediamine.

7. The method of claim 1 wherein said nitroamine is N,=N-bis (Z-nitroisobutyl) -1,3-propanediamine. R, NOR; 8. The method of claim 1 wherein the textile material is 1 1 9. The product produced by the method of claim 1.

References Cited UNITED STATES PATENTS 12 3,475,362 10/ 1969 Romanick et a1. 260--846X 3,476,642 11/1969 Berg et a1 260-846X 3,483,075 12/1969 Schmitt 260846X 5 S. J. LECHERT, 111., Primary Examiner US. Cl. X.R. 

